The present invention relates to a data conversion apparatus, a data conversion method, a printing apparatus using the data conversion apparatus and print control method and, more particularly, to a data conversion apparatus for converting vertical and horizontal orientation of inputted data, a printing apparatus and print control method for performing printing by converting vertical and horizontal orientation of inputted image data.
A serial-scan-type printing apparatus forms an image on a print medium e.g., a print sheet, by scanning a printhead, having plural printing elements arranged in a direction parallel to a conveyance direction of the print medium, in a direction perpendicular to the conveyance direction of the print medium.
Image data, transferred by a host computer (hereinafter referred to as a host) connected to the printing apparatus, consists of pixels arrayed in line in the scanning direction of a printhead. The data having such arrays of pixels is called raster data. In order to transfer image data having such arrays to a printhead, the printing apparatus needs to convert the orientation (arrays) of pixels so as to be adapted to an array of printing elements of the printhead.
Conventionally, such raster-column conversion (hereinafter referred to as H-V conversion) is executed by a processing program which reads plural lines of image data out of a buffer memory and writes converted data back to the buffer while shifting the read data.
However, it has become a trend to perform the H-V conversion by DMA (direct memory access) processing along with demands for high-speed data processing performed by a high-speed printing apparatus. Moreover, to increase the print operation speed, a minimum track printing method has been suggested. According to the minimum track printing method, the current position and the next print occurrence position of a carriage incorporating a printhead are detected and the carriage is moved in the most efficient manner to reduce wasteful operation time.
However, in order to perform the minimum track printing, a buffer storing image data must be scanned to detect positions where printing operations occur and positions where printing operations do not occur within a carriage movable range. Conventionally, such detection required considerable time, interfering with the primary object, i.e. the high-speed printing operation.